I have a 1997 civic hathback. DX. D16y7. It's been parked for a few months. Both my 02 sensors were unplugged and exhaust manifold removed. I need to know which o2 sensor plugs into which plug on the engine harness or if it matters. And the reason I need to know that is because I'm extending the secondary o2 to reach an aftermarket header o2 bung. Before I go cutting and extending wires. And lastly do most of you extend the wiring on the engine harness or the wiring on the o2 sensor. I seen a few write ups on Header installs but haven't seen anyone mention which they cut and extend.

 

Before cat = primary O2 sensor

After cat = secondary O2 sensor

Diagrams below show the 4 wire colors in each of their sensor connectors.